Molecular And Chromosomal Phylogeny Of The Hyracoidea
Chromosomal and molecular parameters were used to determine intraspecific and interspecific relationships of three species of the order Hyracoidea. A diploid chromosome number of 2n = 54 was found to be conserved in all three species and G-band homology was identified for most of the autosomes as well as the sex chromosomes within the Procavia, Heterohyrax and Dendrohyrax genomes. The relative amounts and distribution of constitutive heterochromatin was informative, particularly with regard to D. arboreus. Restriction fragment length polymorphisms (RFLPs) in mitochondrial DNA (mtDNA) revealed 48 haplotypes among 141 hyrax specimens. Procavia capensis capensis clones showed strong geographic patterning and grouped into two geographically and genetically distinct clades. Marked genetic differentiation was also evidenrin H. brucei and D. arboreus which was thought to reflect the influences of habitat specificity, its fragmentation, and the effects of life history on mtDNA gene flow. A high degree of congruence was found between RFLP and sequencing analysis in the determination of interspecific phylogenetic relationships. In addition, phenetic, cladistic and maximum ' likelihood analysis of mtDNA sequences yielded trees with similar topologies. Dendrohyrax was invariably placed as the most primitive and the northern P. c. capensis clade as the most recently derived of the taxa included in the study. The mtDNA data further suggest a close phylogenetic relationship between Procavia and Heterohyrax (which were estimated to have diverged approximately five million years B.P.), a relationship suggested by previous morphological studies as well as by similarities in ecological requirements. Sequencing results place the African elephant (Loxodonta africana) as a sistergroup to the Hyracoidea, while the grouping of the aardvark (Orycteropus afer) with the Paenungulate representatives was not supported by the cytochrome b sequences.